Questions tagged [orbital-elements]

Orbital elements are a set of parameters that uniquely identify a specific orbit.

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Correcting for LAN deviations during launch?

To enter the right orbital plane, you need to target both orbital inclination and longitude of ascending node. The distance from the center of your orbit to your vehicle is so large, however, that ...
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How to launch to achieve predetermined LAAN/RAN?

I'm simulating a rocket and I would like to launch into an orbit with known inclination and longitude of ascending node (LAN/RAAN). My launch azimuth will get me the correct orbital inclination. But ...
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Lowest possible lunar orbit and has any spacecraft achieved it?

Because the Moon has no atmosphere a spacecraft can theoretically cruise at a very low orbit. What is the lowest possible lunar orbit and which spacecraft achieved it? Was it the Lunar Module of ...
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How to find/extract the semi-major axis from a TLE with Skyfield?

I have a TLE: 1 33591U 09005A 21024.46740879 .00000049 00000-0 52095-4 0 9997 2 33591 99.1927 41.5349 0014084 172.6670 187.4709 14.12449679616592 And I would like ...
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Computing a new TLE following a delta-v impulse?

Is there some code or a library out there that can take orbital elements, add a known delta-v component and then compute a new TLE? I found this one https://apps.dtic.mil/dtic/tr/fulltext/u2/a289281....
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Launch azimuth from orbital inclination WRT rotating earth?

The formula for launch azimuth given latitude and target orbital inclination goes like this: $$azm = \sin^{-1} \left(\frac{\cos(inc)}{\cos(lat)}\right)$$ I assume the orbital inclination $inc$ and ...
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How long to reach final orbital inclination?

Consider a rocket launch from Kennedy, latitude 28.5 deg, to a target orbital inclination of 50.6 degrees for rendezvous with the ISS. The launch azimuth for this orbital inclination is roughly 45 deg ...
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Plotting satellite ground track with calculated latitude and longitude at a given moment

I have obtained the Classical Orbital Elements for a satellite on a given epoch, and now I would like to plot them on a 2D map. ...
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145 views

Does it count as orbital flight if one reentered the atmosphere due to its drag after about 1 revolution?

Imagine a spacecraft entered an orbit around the Earth whose perigee is low enough into the atmosphere so that it reenters and lands after a revolution, without having to perform a reentry burn. While ...
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What does diiferent colours in orbital path seen in the CRS 21 launch video indicate?

The SpaceX broadcast of Falcon 9 - CRS 21 launch showed the orbital path of the vehicle differently than previous videos. Separate green lines and rectangualar boxes were visible. What additional ...
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How to plot this orbit?

I have these data for some orbits, without any explanation about meaning of each datum: ...
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When sending astronauts to the ISS, how does each spacecraft sense the other?

When spacecraft with astronauts tries to dock with the ISS, are there special sensors in each used to track the other? Does one usually do the detection, tracking and orientation in order to "...
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264 views

Under what conditions can a non-resonant satellite stay hidden from an observer on the ground?

From the perspective of someone on the ground, a satellite is usually not above the horizon all the time. But can a satellite have such an orbit that it is never above the horizon? Such orbits clearly ...
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Calculating specific dates of reaching apses given orbital elements?

Given a specific date and heliocentric orbital elements ($a, e, i, \Omega, \omega$, mean anomaly) of a spacecraft in a heliocentric orbit, how can we calculate when it will reach perihelion and how ...
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Do I have enough info to find the true anomaly of an orbit?

For a personal coding project, I'm trying to model orbits of satellites around the Earth. I take in some values from a user and use them to determine the shape of the orbit. I want to model the ...
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Graph Eccentrity Vector in x and y Component

I have one year eccentricity value (the eccentricity magnitude only). I want to know the eccentricity vector in x and y component, so I use this below equation to get it (credit: Hengian Li): After ...
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59 views

Is it possible to represent an orbit with just a periapsis position and 2 angular velocities?

I was thinking of how complex the orbital elements are and got to wondering whether you can represent orbits in a more simple way. If you start with an ECI coordinate frame and you know the spherical ...
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Direct conversion of Keplerian orbital elements to Equatorial coordinate system

In the context of a computer simulation of satellites that orbit earth, I am looking for a (accurate) method for converting Keplerian orbital elements directly to Equatorial coordinate system. The ...
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Most efficient (computationally) orbit propagation for simplified J2 effects

I am looking into modeling large scale constellation (hundreds of satellites) and there coverage over earth given a defined conical FOV. The simplified process is a user defines: Constellation (...
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1answer
108 views

What is the maximum apogee a Dragon spacecraft can reach?

What is the maximum apogee a Crew Dragon can reach in a highly elliptical orbit (by both the Falcon 9 and the Falcon Heavy)? There is a planned touristic mission in which the current apogee record of ...
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216 views

What is the maximum apogee a Space Shuttle could have reached?

What is the maximum apogee a Space Shuttle (and which one of the five space-flying Shuttles?) ever reached and what is the maximum one it could have reached? A Space Shuttle never exceeded the apogee ...
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193 views

Were/Are the Space Shuttle or the Falcon 9 Dragon capable of achieving an elliptical orbit on whose apogee you'd see the entire Earth?

Was the Space Shuttle and is the Crew Dragon capable of achieving a highly elliptical orbit on whose apogee you could see the entire planet Earth? There will be a touristic flight soon in which an ...
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Keplerian to cartesian elements issue

I am trying to convert between keplerian orbital elements to cartesian position and velocity but something is going wrong. The issue is that I (as a check) compute some keplerian orbital elements with ...
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Compute eccentricity and angular momentum vectors of a binary

I having some trouble finding the direction vectors (in 3D) of the eccentricity and angular momentum of a binary. The issue is that the binary has only been described in Keplerian orbital elements and ...
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2answers
435 views

Visualising orbits from different viewpoints in Python

I have a python program that I use to visualise a planetary orbital system. I convert the orbits to xyz coordinates and then have a basic orrery that views the system from 'above', by simply plotting ...
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Interplanetary space mission debris orbits

I was wondering if anyone knew about a database of orbits for debris from previous interplanetary space missions. I am referring to debris or expired missions by NASA, ESA, JAXA, etc. I know there are ...
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1answer
567 views

How to calculate position and velocity from given orbital elements?

I have some orbit, with a given semi-major axis, inclination, eccentricity, longitude of ascending node, argument of periapsis, and true anomaly. How can I, from this, calculate the position and ...
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245 views

How to change RAAN with 250 m/s DV?

I'm performing a transfer between 2 orbits with different RAAN (other orbital parameters are same). The perigee altitude of the orbits is 1000km, the apogee is <...
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Will crewed vehicles ever follow multi-flyby trajectories?

A while ago, I asked a similar question here, but I think it was confusing, so nobody answered. Two questions: This one is a bit subjective: Do you think that lengthy (+5y) multi-flyby trajectories ...
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Given an arrival date, is there a way to calculate the declination and right ascension of the arrival asymptote into Mars?

I am designing an Earth-Mars transfer. The launch window is 03-Jul-2026 (departure from Earth) & 22-Jun-2028 (Mars arrival). The declination and right ascension for the departure asymptote from ...
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1answer
97 views

How significant is orbit propagator choice/error when considering a year-long satellite coverage simulation, and which is the most appropriate?

I'm currently considering a project to simulate the (Earth-seeing) coverage of 1 or more satellites over the course of a year. The point would be to compare how different orbits result in different ...
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1answer
91 views

Need javascript to solve xyz for a kepler

I have a python program that I use to calculate the xyz positions of a point in a kepler orbit. https://github.com/sczesla/PyAstronomy/blob/master/src/pyasl/asl/keplerOrbit.py It takes the following ...
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Is it possible to achieve a perfectly circular orbit?

Is it possible for a spacecraft to achieve an orbit around a celestial body that has no orbital eccentricity at all? The smallest orbital eccentricity of a natural satellite is that of Triton's orbit ...
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Cartesian vectors to keplerian orbital elements of binary system

I am looking to code a a function that converts my 3d position and 3d velocity of a binary system into keplerian orbital elements of the system. I have seen a few other posts on this but they always ...
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1answer
108 views

Different results for Orbital Period?

I am making a hypothetical solar system with random masses and distances (but still physically and mathematically accurate). I want to calculate the trajectory of a spacecraft, and to do that, I need ...
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59 views

Angles only Orbit Determination for LEO satellites

I have a script that uses the Gauss method for Prilimanry Orbit determination of satellites using 3 sets of ra-dec and the corresponding LST (adapted from the MatLab example given in the appendix of ...
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1answer
86 views

Is it possible to update an existing TLE using new data?

I'm writing a simulation a space surveillance telescope. The population of satellites it observes is initialized using TLEs, and the telescope also is given these TLEs at the beginning of the night ...
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1answer
185 views

How can you determine the nature of an object from its flight path angle, velocity, and radius alone?

Assuming that a defense system is capable of determining an object's flight path angle ($\gamma$), velocity (v), and radius (r), how could one differentiate between an ICBM, a satellite, or a solar ...
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How do you calculate shift in argument of periapsis for a not instantaneous burn assuming you're starting in circular orbit?

Most times we assume that burns are instantaneous, in this case if you burn (without a radial component) at the periapsis or apoapsis there is no shift in argument. Let's say the engine is weak and ...
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441 views

What is the reason for secondary oscillations in apogee and perigee plots for objects 41332 and 41333?

This answer provides quite interesting plots of apogee and perigee for objects 41332 and 41333. The primary (sine wave -like) oscillations are probably due to perturbations caused by potential ...
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115 views

How satellite orbital vacancies are determined?

Before a new satellite is launched, its desired orbital altitude, inclination is determined. Now with thousands of satellites already in orbit at different altitudes, how do we know if our desired ...
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1answer
293 views

Geocentric latitude and longitude of sub-satellite point

I was trying to derive the expressions for the geocentric latitude and longitude of the sub-satellite point using Keplerian elements. The final equations connecting the combination of the Keplerian ...
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1answer
49 views

Naming conventions concerning element sets/coordinate systems/reference frames

Suppose I have two ECI Cartesian state vectors: One in the TEME frame of reference and one in the GCRF frame of reference. Suppose I now convert both state vectors to Classical Orbital Elements (COE). ...
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Issue with SGP4 modelling from scratch in MATLAB

I am trying to develop the code from this source , this research paper and from this too as same as bibliography of that aforementioned source. So, here as you can see at page 14, they have defined ...
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2answers
855 views

How can I calculate if a satellite is currently in sunlight or eclipse using pyEphem or Skyfield (preferred)?

I'd like to add this to some existing python scripts to model cubesat battery life and payload temperature but the math escapes me.
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Orbital period from TLE data [duplicate]

Is there a way to calculate the orbital period from the Two Line Element (TLE) data?
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Mean to Osculating conversion for non-J2 averaged elements

What is the appropriate technique to convert mean elements (true anomaly averaged) into osculating elements when the model has J2, SRP, drag and additional forces modeled. Brouwer's transformation is ...
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How can I convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates (ECI)?

I need to convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates relative to earth center (ECI) -- i.e., position x,y,z and velocity x,y,z. Standard Anaconda Python ...
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477 views

How frequent do TLEs of LEO satellites change?

I was doing some MATLAB simulations on LEO satellites using TLEs obtained from n2yo websites and I observed that n2yo was displaying a different TLE for the same satellite after a few days. I don't ...
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How do I calculate the change in the argument of periapsis after a plane change maneuver?

Let's say I have a spacecraft in an initial geocentric orbit with the following parameters: a = 7,960,000 m, e = 0.010, $\Omega$ = 180$^{\circ}$, i = 98$^{\circ}$, $\omega$ = 90$^{\circ}$, $\theta_0$ =...